Testing a capacitor
Instructor
Joined: Sep 2017
Posts: 169
Likes: 20
From: Westlake Ohio
To test the capacitor with a multimeter, set the meter to read in the high ohms range, somewhere above 10k and 1m ohms. Touch the meter leads to the corresponding leads on the capacitor, red to positive and black to negative. The meter should start at zero and then moving slowly toward infinity.
Thread Starter
Melting Slicks
Joined: Sep 2006
Posts: 2,795
Likes: 466
From: Wichita Kansas
To test the capacitor with a multimeter, set the meter to read in the high ohms range, somewhere above 10k and 1m ohms. Touch the meter leads to the corresponding leads on the capacitor, red to positive and black to negative. The meter should start at zero and then moving slowly toward infinity.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,112
From: Crossville TN
It doesn't matter which way you put the leads to the capacitor. And, when you do that test, you should follow it with another test with the leads reversed. The multi-meter needle should make the same movement each time. If it doesn't, that component is "toast". I highly doubt that a 40 year-old electrolytic would still have any liquid electrolyte left in it.
P.S. That is simply a noise suppression capacitor for limiting radio noise. You probably don't need it, anyway.
P.S. That is simply a noise suppression capacitor for limiting radio noise. You probably don't need it, anyway.
Le Mans Master
Joined: Jan 2001
Posts: 6,656
Likes: 1,357
The lead on the capacitor that is screwed onto the back of my Tach separated from the cap itself.... I just bought a generic points ignition capacitor and soldered (with heat shrink) that oddball terminal connector onto the new ignition capacitor so I could just plug it back into the harness. Not sure I need it since I hardly use the radio but I did it since it was easy enough.
Instructor
Joined: Oct 2016
Posts: 211
Likes: 20
From: Raleigh NC
Yes
You can hold one meter lead onto the case but don't touch the other when testing. The meter will read through your body and you won't get an accurate reading.
If using the ohm scale check the cap then reverse the leads. You should get meter deflection each time then the meter settles to infinity.
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Thread Starter
Melting Slicks
Joined: Sep 2006
Posts: 2,795
Likes: 466
From: Wichita Kansas
It doesn't matter which way you put the leads to the capacitor. And, when you do that test, you should follow it with another test with the leads reversed. The multi-meter needle should make the same movement each time. If it doesn't, that component is "toast". I highly doubt that a 40 year-old electrolytic would still have any liquid electrolyte left in it.
P.S. That is simply a noise suppression capacitor for limiting radio noise. You probably don't need it, anyway.
P.S. That is simply a noise suppression capacitor for limiting radio noise. You probably don't need it, anyway.
Pro
Joined: Nov 2013
Posts: 730
Likes: 37
From: Catoosa Okla
Yes. Take it and pull a working spark plug wire from a working engine, even a Ford will do for this. Take the wire from the capacitor and put it in the plug wire where the spark plug would go, then ground the capacitor can while someone spins the motor over. This will put a good 40,000 volts or so into the capacitor.
Then, carefully remove the wire from the spark plug boot being very careful not to touch the wire end and the metal capacitor at the same time.
Then, toss it on a table frequented by people, and watch what happens. Without a doubt, someone will pick it up and will touch the wire and the capacitor can at the same time.
Watch for uncontrollable movement followed with cuss words or wet stains in the crotch area. Any or all of the above verifies proper capacitor operation.
*This test can be performed with absolutely no test tools required whatsoever other than a human guinni pig
Then, carefully remove the wire from the spark plug boot being very careful not to touch the wire end and the metal capacitor at the same time.
Then, toss it on a table frequented by people, and watch what happens. Without a doubt, someone will pick it up and will touch the wire and the capacitor can at the same time.
Watch for uncontrollable movement followed with cuss words or wet stains in the crotch area. Any or all of the above verifies proper capacitor operation.
*This test can be performed with absolutely no test tools required whatsoever other than a human guinni pig
Safety Car
Joined: May 2008
Posts: 3,745
Likes: 712
From: Lafayette Louisiana
Too funny!
Yes. Take it and pull a working spark plug wire from a working engine, even a Ford will do for this. Take the wire from the capacitor and put it in the plug wire where the spark plug would go, then ground the capacitor can while someone spins the motor over. This will put a good 40,000 volts or so into the capacitor.
Then, carefully remove the wire from the spark plug boot being very careful not to touch the wire end and the metal capacitor at the same time.
Then, toss it on a table frequented by people, and watch what happens. Without a doubt, someone will pick it up and will touch the wire and the capacitor can at the same time.
Watch for uncontrollable movement followed with cuss words or wet stains in the crotch area. Any or all of the above verifies proper capacitor operation.
*This test can be performed with absolutely no test tools required whatsoever other than a human guinni pig
Then, carefully remove the wire from the spark plug boot being very careful not to touch the wire end and the metal capacitor at the same time.
Then, toss it on a table frequented by people, and watch what happens. Without a doubt, someone will pick it up and will touch the wire and the capacitor can at the same time.
Watch for uncontrollable movement followed with cuss words or wet stains in the crotch area. Any or all of the above verifies proper capacitor operation.
*This test can be performed with absolutely no test tools required whatsoever other than a human guinni pig
Tooooo funny!
Sounds like some of my friends!
